diff --git a/.travis.yml b/.travis.yml
index fb2ec6fe4..ef557b694 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,8 +21,6 @@ matrix:
 
     # Linux/clang
     # https://apt.llvm.org/
-    - os: linux
-      env: COMPILER=clang++-3.5
     - os: linux
       env: COMPILER=clang++-3.6
     - os: linux
@@ -45,27 +43,25 @@ matrix:
     - os: osx
       osx_image: xcode7.3
       env: OSX_VERSION=10.11
+    - os: osx
+      osx_image: xcode8
+      env: OSX_VERSION=10.11
     - os: osx
       osx_image: xcode8.3
       env: OSX_VERSION=10.12
     - os: osx
-      osx_image: xcode9.3
+      osx_image: xcode9.2
+      env: OSX_VERSION=10.12
+    - os: osx
+      osx_image: xcode9.4
       env: OSX_VERSION=10.13
     - os: osx
-      osx_image: xcode9.3
+      osx_image: xcode9.4
       env: OSX_VERSION=10.13 USE_OPENSSL_1_1=yes
 
   allow_failures:
-    - env: COMPILER=g++-6
-    - env: COMPILER=g++-7
-    - env: COMPILER=g++-8
-    - env: COMPILER=clang++-3.5
     - env: COMPILER=clang++-3.6
     - env: COMPILER=clang++-3.7 DISABLE_ASAN=yes
-    - env: COMPILER=clang++-4.0
-    - env: COMPILER=clang++-5.0
-    - env: COMPILER=clang++-6.0
-    - env: COMPILER=clang++-7
     - env: OSX_VERSION=10.13 USE_OPENSSL_1_1=yes
 
   fast_finish: true
diff --git a/.waf-tools/default-compiler-flags.py b/.waf-tools/default-compiler-flags.py
index e69029029..2be9d9041 100644
--- a/.waf-tools/default-compiler-flags.py
+++ b/.waf-tools/default-compiler-flags.py
@@ -20,9 +20,9 @@ def configure(conf):
                       'The minimum supported gcc version is 5.3.0.')
         conf.flags = GccFlags()
     elif cxx == 'clang':
-        if ccver < (3, 5, 0):
+        if ccver < (3, 6, 0):
             errmsg = ('The version of clang you are using is too old.\n'
-                      'The minimum supported clang version is 3.5.0.')
+                      'The minimum supported clang version is 3.6.0.')
         conf.flags = ClangFlags()
     else:
         warnmsg = 'Note: %s compiler is unsupported' % cxx
diff --git a/docs/INSTALL.rst b/docs/INSTALL.rst
index 0eaf52ac0..5d94e351d 100644
--- a/docs/INSTALL.rst
+++ b/docs/INSTALL.rst
@@ -29,7 +29,7 @@ Prerequisites
 Required:
 ~~~~~~~~~
 
--  GCC >= 5.3, or clang >= 3.5
+-  GCC >= 5.3, or clang >= 3.6
 -  ``python2`` >= 2.7, or ``python3`` >= 3.4
 -  ``libsqlite3``
 -  OpenSSL >= 1.0.2